It is known to have extension devices which enable placement of the gun against the ceiling by an operator standing on the floor. Because the gun trigger, intended for firing with the index finger, is thus greatly distanced from the operator, expedients such a ropes to effect firing have been employed. This operation is cumbersome. It is further known, as described in U.S. Pat. No. 3,797,721, that a firing charge can be detonated by having the fastener itself act as the firing pin. The charge is rim-fired by the fastener being displaced into the firing chamber by pressing the fastener against the ceiling, with or without an extension device, and then hitting the device with force sufficient to fire it.
This patented system requires special charges and fasteners which are much less widely available than the standard charges and ceiling clip-fastener assemblies used with the Hilti.RTM. and Ramset.RTM. guns. Most installers own the standard guns, using them for studs, flooring, and other construction jobs in addition to ceiling installation, and prefer the convenience of standard and widely available components.